Some Democrats already being mentioned as potential candidates include former Rep. Earl Pomeroy, radio host Joel Heitkamp and former state Attorney General Heidi Heitkamp.

Facing a tough re-election, former Sen. Byron Dorgan (D-N.D.) retired last year, and Pomeroy was defeated for re-election by Republican Rick Berg. Dorgan was replaced by former Gov. John Hoeven (R), who won easily.

In a letter obtained by Roll Call, Conrad, the Budget Committee chairman, wrote that he will not seek re-election in 2012.&nbsp;

&ldquo;There are serious challenges facing our State and nation, like a $14 trillion debt and America's dependence on foreign oil,&rdquo; the Democrat wrote. &ldquo;It is more important I spend my time and energy trying to solve these problems than to be distracted by a campaign for reelection.&rdquo;&nbsp;

Conrad&rsquo;s priorities over the next two years include putting the country &ldquo;on a sound fiscal course,&rdquo; reducing the country&rsquo;s &ldquo;dependence on foreign energy,&rdquo; working on a new farm bill, advancing &ldquo;permanent flood control for the Red River Valley&rdquo; and addressing &ldquo;the disaster in the Devils Lake Basin,&rdquo; he said.

&ldquo;Although I will not seek reelection, the work is not done,&rdquo; Conrad wrote. &ldquo;I will continue to do my level best for both North Dakota and the nation over the final two years of my term.&rdquo;&nbsp;